The present invention relates to a feed for ruminants which is produced by using as the main raw material vegetable fiber materials which ruminants are incapable of digesting, and to the process for producing same.
Assorted feeds (concentrated feeds) which have been produced as livestock feeds, are generally designed so as to contain calculated amounts of nutritious substances needed by animals, and usually the content of solid fiber materials is relatively low.
Feeds taken by ruminants such as cattle and sheep stay in their paunch (anterior stomach, i.e. the rumen-reticulum) for a relatively long period of time. Meanwhile, they are moderately mixed by gastric motion, fermented by the action of various bacilli and enzymes in the paunches and finally absorbed as nutrious substances. However, when the content of solid fiber materials in the above feeds is too low, such digestive mixing and fermentation cannot be adequately carried out, thus creating various problems. Therefore, in case of foddering ruminants with assorted feeds, it is necessary to blend most feeds with crude or rough feeds mainly composed of solid fiber materials.
Further, it is required that such crude feeds not only contain a sufficient amount of solid fiber materials but also that they be digestible. Grass or pasture is a suitable fiber-containing crude feed, but in some cases it may be replaced with rice straw which is comparatively digestible by ruminants.
However, because of recent shortages and rise in the prices of these feed resources, it has become desirable from the viewpoint of livestock management to utilize as crude feeds various vegetable fiber resources such as sawdust and waste paper which have not previously been successfully used as livestock feeds. Toward this end, many attempts have been made but to date use of such indigestible vegetable fiber materials as livestock feed has proven impractical because they are indigestible and do not have suitable taste. For example, a crude livestock feed has been prepared by fermenting sawdust in the presence of Bacillus subtilis. The crude feed thus obtained has an improved taste and can be used together with grass or pasture to increase the quantity of livestock feeds. However, it lacks nutritional value and otherwise has little value as to livestock feed because its indigestibility is no better than the sawdust from which it is produced. Moreover, the livestock feed thus obtained is expensive, because the fermentation of sawdust takes a considerable period of time and requires a troublesome mixing operation and special apparatus.
Further, there is known another process for producing a crude feed, where more or less hard vegetable fiberous materials such as rice hulls are treated with ammonia at a high pressure within the range of about 80 to 100 atm. to destroy their fiber structure. However, the above process has little utility because it requires special and large-scale apparatus which can stand the unusually high temperature and pressure. It is also possible to produce a crude livestock feed by mixing assorted feeds with the above-mentioned indigestible vegetable fibers. However, the serious drawback of low nutritional value remains. Additionally, extremely hard vegetable fibers such as wood chips cannot be added to assorted feeds.